1. Field of the Invention
The invention relates to a method for winding a winding wire onto a winding body, an arrangement for winding a winding wire onto a winding body, and an associated magnet assembly for a solenoid valve.
2. Description of the Prior Art
In modern brake systems and driver assist systems, which include for example an antilock brake system (ABS), a traction control system (TCS), or an electronic stability program system (ESP system), solenoid valves are used for pressure modulation. Broken down roughly into their basic components, these solenoid valves are composed of a valve cartridge that is calk-mounted in a fluid assembly, and a magnet assembly installed as a rule in an associated control unit. The magnet assembly is activated with electrical activation signals in order to produce a corresponding magnetic field; the magnet assembly includes a wire winding that is wound onto a winding support and has a predetermined number of turns, a covering disk, and a housing casing. The covering disk here, functioning as a magnetic circuit component, is press-fitted into the housing casing in order to complete the magnetic circuit of the magnet assembly.
For the winding procedure, in which a winding wire is wound onto the winding body, a winding method is known from the prior art, which uses a so-called “wire remnant-free” winding. In this method, the winding wire is fixed in place not by means of an auxiliary pin but instead by means of an additional clamping during the changing of the winding body. In other words, a winding wire end of a preceding magnet assembly is used as the beginning of the subsequent magnet assembly. In this case, the winding wire is fixed in the winding body by means of a clamping in a wire-receiving slot of an electrical connection dome that is part of the winding body. The wire-receiving slot is embodied for connecting to the winding wire by forming a cut-and-clamped connection. Since the electrical connection dome is embodied in the form of an injection-molded plastic part, it is difficult, from an injection molding standpoint, to maintain the required tolerance for the slot width. In addition, process influences after the injection molding, such as shrinkage and water absorption are not, as a rule, taken into account in the component measurements. For this reason, the winding wire can, for example due to being pressed too weakly into the wire-receiving slot, slip back out of the wire-receiving slot during the cutting procedure on the winding machine or in subsequent assembly procedures, such as packing, transport, etc. and in the handling of the wound winding body. With too powerful a clamping, the winding wire cannot, for example, rest completely against a wire support and can separate upward from it. This can result in an incorrect positioning of the winding wire in which the contacting region toward the cutting blade is no longer present or under some circumstances, lies outside the contacting zone in the region of the cutting blade opening. In addition, a potential excessive back-slippage of the winding wire can result in a contact between the winding wire and the housing casing of the magnet assembly. Vibrations that occur with field loading can result in a shearing-through of the insulation of the winding wire and thus to a short-circuiting and therefore also a failure of the magnet assembly.